The lava lake, known as Loki Patera, is the largest on the surface at 200 kilometers (125 miles) across. It’s so big, that it dwarves lava lakes seen here on Earth, where our largest known lava lake is a mere 200 meters (600 feet) in width.
Using a process known as occultation, a team from the University of California, Berkeley (UCB) was able to indirectly observe the motion of the waves across Loki Patera to infer the size of the lake. Using this process, they were able to infer that the lake was shifting in temperature from 270 Kelvin to 330 Kelvin which suggests an “overturn” in the volcanic process – that can lead to the formation of a crust, or land.
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.
As the team watched Europa cross Io’s path using the Large Binocular Telescope Observatory in Arizona, they were able to get a full look at Loki Patera. The occultation process blocked out all of the external light and allowed for the team to focus only on the heat emitted from the Lake, an impressive feat considering there is over 400 active volcanoes on the surface of Io.